| Magnetic and magneto-optic properties and microstructure of coevaporated Tb/Fe multilayer thin films as functions of the Tb layer thickness, the ratio of Tb and Fe layer thickness and the period were studied by using a Torque magnetometer, a polar Kerr hysteresisgraphy, a Hall effect measurement apparatus and a TEM. The multilayered films showed that the larger perpendicular anisotropy energy than that of the amorphous TbFe alloy thin films. The multilayered films showed superior properties when they were not piled-up with monatomic layer but with two atomic layers of Tb. Therefore, it was speculated that the directional Tb-Tb and Fe-Fe pairs contribute to the the large perpendicular anisotropy as well as the Tb-Fe pairs to do. A dead zone which has no magnetization or weak magnetization compared to strongly exchange-coupled region was formed at above 3 atomic layer of Tb. Accordingly, the saturation magnetization of the 4 atomic layered film was smaller and decreased more rapidly than that of the 3 atomic layered film in the Tb-rich region, and oppposite phenomenon was appeared in the Fe-rich region. |
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